Titan's rivers point to Earth-like erosion

Findings at MIT suggest that Titan's geological phenomena may bear remarkably close similarities to those found on Earth (Image: NASA/JPL/USGS)

After revealing the strong possibility of an underground liquid water ocean on Titan, further analysis of radar data collected by a flyby of the Huygens/Cassini spacecraft is now suggesting that, despite a dramatically different composition, Saturn's largest moon may share many of Earth's geological processes. By studying those features, exogeologists are beginning to answer some pressing questions on the forces that shaped Titan's geological past.

Titan's thick, hazy atmosphere had impeded the study of geological features in its landscape until 2004, when the Cassini spacecraft used radar to image portions of its surface. The spacecraft returned to us pictures of a very unique landscape in which rivers of liquid methane are slowly carving their way into a solid surface of water ice.

What puzzled scientists, however, was something else entirely. Titan is about four billion years old, but it appears much younger, between 100 million and one billion years old. For its age, Titan has an inexplicably low number of impact craters, and its rivers produce a much slower erosion than would be expected.

A team led by MIT geology professor Taylor Perron set out to find an explanation. The researchers started by mapping 52 river networks from four different regions of Titan and, applying a model originally designed to study river networks on Earth, found similarities with the early stages of the evolution of terrestrial rivers, particularly to those near newly formed volcanic and glaciated landscapes.

This suggests that geologic processes have reshaped the moon's icy surface in the recent past, and that such phenomena are quite similar to those found on Earth. On our planet, continents are constantly eroding or being covered with sediment, and the same may be true for Titan, where tectonic upheaval, eruptions of icy lava, erosion and sedimentation by liquid methane rivers are thought to be responsible for this uncharacteristically young-looking moon.